Have you ever felt pesky drafts around your home? Drafts and air leakage can be a concern for a lot of homeowners. It’s incredibly frustrating when your heating or cooling bills skyrocket in the middle of the most intense seasons. A blower door test is the most effective way to determine the location and extent of the air leakage.

So, what is a blower door test? A blower door test is a diagnostic tool used on buildings to quantify the amount of air leakage through their enclosure. During this test, a calibrated fan is installed in an otherwise sealed door or window while all the other openings to the exterior are closed. When the fan is turned on, it creates a pressure difference between the outside and the inside. The fan sucks the air out of the home, causing it to come in through whatever pathways it can find — many of which are unintentional.

Exterior building enclosure leakage impacts our health and well-being. Gaps and cracks in the air barrier and surrounding connections of a home or building can cause several issues. These gaps are more than just a place for bugs, dust, and pollen to get in. They also allow cold or warm air, moisture, and contaminants like smoke to enter.

Depending on your climate, this leakage can have detrimental effects. In humid climates, high amounts of envelope leakage can cause excessive amounts of moisture to infiltrate the home, making it uncomfortably sticky and more susceptible to issues such as mould.

In drier climates, dry air comes in during the winter months. It creates an uncomfortably dry environment that can cause dry sinuses and static electricity and even increase the spread of viruses. These leaks also impact energy usage, as the air that is heated or cooled escapes the building more quickly, increasing air conditioner or heater runtimes.

People concerned about health, comfort and efficiency should consider testing their home to see how it measures and locate aspects that can be improved.

When to get a blower door test.

In new home construction or during renovations, performing air leakage testing at different stages of construction can help diagnose issues and fix them while the primary air barrier is still accessible. Once you locate where the leakage is coming from, recommendations can be made to address those areas before installing drywall.

Aside from code compliance or indoor air quality concerns, another reason to get a blower door test is to size your furnace or air conditioner properly.

Air infiltration is critical to heat losses and gains in a home. It is often the largest source of winter heat loss in older houses and cold climates. Errors in infiltration inputs can lead to oversizing or undersizing heating and cooling equipment. How leaky or tight your home is can change how much heating/humidification or cooling/dehumidification you need.